The pdd genes encoding adenosylcobalamin-dependent diol dehydrase of Klebsiella oxytoca were cloned by using a synthetic oligodeoxyribonucleotide as a hybridization probe followed by measuring the enzyme activity of each clone. Five clones of Escherichia coli exhibited diol dehydrase activity. At least one of them was shown to express diol dehydrase genes under control of their own promoter. Sequence analysis of the DNA fragments found in common in the inserts of these five clones and the flanking regions revealed four open reading frames separated by 10-18 base pairs. The sequential three open reading frames from the second to the fourth (pddA, pddB, and pddC genes) encoded polypeptides of 554, 224, and 173 amino acid residues with predicted molecular weights of 60,348 (alpha), 24,113 (beta), and 19,173 (gamma), respectively. Overexpression of these three genes in E. coli produced more than 50-fold higher level of functional apodiol dehydrase than that in K. oxytoca. The recombinant enzyme was indistinguishable from the wild-type one of K. oxytoca by the criteria of polyacrylamide gel electrophoretic and immunochemical properties. It was thus concluded that these three gene products are the subunits of functional diol dehydrase. Comparisons of the deduced amino acid sequences of the three subunits with other proteins failed to reveal any apparent homology.

This review has outlined the strategies and tactics of using arynes in the total syntheses of polycyclic natural products.

Consomic strains, also known as chromosome substitution strains, are powerful tools for assigning polygenes that control quantitative complex traits to specific chromosomes. Here, we report generation of a full set of mouse consomic strains, in which each chromosome of the common laboratory strain C57BL/6J (B6) is replaced by its counterpart from the inbred strain MSM/Ms, which is derived from Japanese wild mouse, Mus musculus molossinus. The genome sequence of MSM/Ms is divergent from that of B6, whose genome is predominantly derived from Western European wild mouse, Mus musculus domesticus. MSM/Ms exhibits a number of quantitative complex traits markedly different from those of B6. We systematically determined phenotypes of these inter-subspecific consomic strains, focusing on complex traits related to reproduction, growth, and energy metabolism. We successfully detected more than 200 statistically significant QTLs affecting 26 traits. Furthermore, phenotyping of the consomic strains revealed that the measured values for quantitative complex traits often far exceed the range between B6 host and MSM/Ms donor strains; this may result from segregation of alleles or nonadditive interactions among multiple genes derived from the two mouse subspecies (that is, epistasis). Taken together, the results suggest that the inter-subspecific consomic strains will be very useful for identification of latent genetic components underlying quantitative complex traits.

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